The former butler for Pope Benedict says he feels guilty for "having betrayed the trust of the Holy Father."

Paolo Gabriele, a 46-year-old father of three, appeared in a Vatican courtroom Tuesday on charges of aggravated theft for allegedly stealing some of the pontiff's personal papers.

Gabriele took the stand in his own defense and admitted he photocopied private correspondences to expose evil and corruption in the church, but steadfastly denied he was guilty of aggravated theft.

Prosecutors say Gabriele admitted during an interrogation before the trial that he leaked the documents to a journalist writing a book on alleged corruption in the church. Gabrielle faces up to four years in prison if convicted. Many Vatican observers say they expect Pope Benedict to pardon Gabriele if he is convicted.

Many Vatican observers say they expect Pope Benedict to pardon Gabriele if he is convicted.

Meanwhile, the judge is ordering an investigation into the Vatican police force for its treatment of Gabriele.

Gabriele's lawyer alleged Tuesday that police held Gabriele in a tiny room for 15 to 20 days, leaving the lights on constantly.

The Vatican confirmed an inquiry has been opened but defended the treatment of Gabriele saying the jail cell conformed to international standards and that Gabriele was later moved to a bigger cell.